A system is disclosed for detecting the precise location of a reflective element in a video field wherein the determined location is subsequently utilized to generate a graphic to be added to a foreground video scene utilizing compositing techniques well known in the art. The system has application in many situations wherein it is desired to generate an image which is a composite of a foreground and background video. For example, weather broadcasts frequently utilize a composite video image wherein the weather person appears in front of a backing (typically blue) and the background video source is a weather map with clouds, temperatures, cold fronts and other graphics which may be added to the weather map in a predetermined sequence. Frequently, the weather person points to a position on the blue backing which corresponds to a position on the weather map at which a desired graphic is to appear, and, so long as the weather person""s hand position and timing are correct, the graphic, such as a temperature for a particular city, appears in the composite video. However, with such systems, all graphics to be displayed must be positioned in advance and a sequence must be created which cannot be dynamically changed by the weather person other than, perhaps, to skip through or to the end of a particular preprogrammed sequence.
With the invented system, since a signal is generated specifying a precise point in the foreground video scene identifying a position the weather person is pointing at, as represented by a reflective element, graphics can be repositioned as desired by the weather person or lines or other graphic elements can be generated which track the movement of the reflective element.
Another possible use of the invented system is by a football analyst who can diagram a play showing the movement of various players by moving the reflective element across a frame of a background video scene of the playing field with the players lined up at the beginning of the play. The invention may also be used by military analysts to illustrate movement by ground, sea or air forces, either for public consumption or field officers, or wherever it is desired to illustrate a background video scene by a pointer device.
The invention is an improvement of the system described in co-pending application Ser. No. 07/867,048 filed Apr. 10, 1992 owned by the present assignee which is directed to an analog system for detecting the position of colored reflective objects in a video field having a spherical or generally spherical shape. The present invention is a digital system which is able to detect colored reflective objects which are much smaller in size than can be detected by the prior system and which may be of any shape and color.